''My mother is just totally upset,'' said their son, Robert. ''Everything she had in the world was in that house: family pictures, irreplaceable stuff. It's really tragic.''

Firefighters were called to the single-story house about 12:30 a.m. and had the blaze under control about an hour later, said Cmdr. Ed Jones, of the Orange County Fire Department. But firefighters and investigators remained on the scene until 5 a.m.

Jones said the fire began in a bathroom-utility room area and spread to the rest of the house. He said the house was insured for $44,000 and everything was lost. No one was hurt.

The fire is believed to have started accidentally, Jones said. The couple left home Saturday morning and were to return Monday night, their son said.

''The house was all locked up,'' he said. ''Nobody was there all weekend. This is a real shock to them. I guess you don't think things like this will happen.''

The couple had lived at the house about 12 years, their son said. He said his parents probably will stay with his brother. The couple could not be reached for comment.